Method and apparatus for making endless sewn fabric



Aug. 5, 1969 .c. A. LEE ET AL METHOD AND APPARATUS FOR MAKING mmmass SEWN FABRIC Fi-led April 29. 1966 4 Sheets-Sheet 1 INVENTORS cmzzsz'. 4E5

Aug. 5, 1969 c. A. LEE ET AL METHOD AND APPARATUS FOR MAKING ENDLESS SEWN FABRIC Filed April 29, 1966 4 Sheets-Sheet 2 INVENTORS wdiii/v/eifldick mm mmqm m ATTORNEYS Aug. 5, 1969 LEE ET AL 3,459,612

METHOD AND APPARATUS FOR MAKING ENDLESS SEWN FABRIC Filed April 29, 1966 4 $heet$-$h6et 5 TO MOTOR 140 F1 5' 204 CLUTCH 18' J ALLifigATE POWER SUPPLY INVENTORS 67/491554 LEE WAfFZ'WZ/Z/PSR'K v ML,

Aug. 5, 1969 c, LEE ETAL METHOD AND APPARATUS FOR MAKING ENDLESS SEWN FABRIC FiledApr'il 29, 1966 4 Sheets-Sheet &

m M T E mfiw N v. 2 4%. R /M WM m W MMiMhT%iZ/- 3,459,612 METHOD AND APPARATUS FOR MAKING ENDLESS SEWN FABRIC Charles A. Lee and Warren R. Fur-beck, Knoxville,

Tenn., assignors, by mesne assignments, to Appleton Wire Works Corporation, Appleton, Wis, a corporation of Wisconsin Filed Apr. 29, 1966, Ser. No. 546,380 Int. Cl. 1832b 7/08; D06c 1/00 U.S. Cl. 15684 24 Claims This invention relates to a method and apparatus for forming fabrics by sewing. More particularly, it relates to a method and apparatus for making endless fabrics in which sewn filaments are sewn in one direction across rack filaments running endlessly in another direction.

This invention is directed to a method and apparatus for making fabrics such as the fabrics described in the co-pending application of Charles A. Lee, Ser. No. 431,030, filed Feb. 8, 1965 for Sewn Fabric and Method of Manufacture, nOW abandoned. Such fabrics are formed by stitching sewn filaments across a plurality of rack filaments, preferably with non-woven filler filaments therebetween. The present invention is particularly directed to a method and apparatus for making such fabrics endlessly and more particularly to such method and apparatus wherein the entire fabrication is performed on the same rack.

In the preferred form of the invention, the rack filaments comprise a single continuous rack filament wound a number of times over a predetermined path defined by a plurality of rolls disposed in predetermined relative position to form a rack. As the filament is wound on, each turn is captured, as between particular teeth of a comb, so that upon completion of the winding on, the loops of the rack filament are in predetermined laterally spaced relation upon the rack. The two ends of the rack filament may then be passed over pulleys and tied together so that the rack filament then passes in a multiloop closed path. Because the single filament is then itself endless, the tension in each loop is the same. If the tension is not equalized when the filament is first wound on, it can be equalized by moving the loops together several times about the predetermined path on the rack. The rack may then be squared and predetermined equalized tension placed in the loops of rack filament, as by pulling on one of the rolls. The filaments are then ready for the sewing operation, although prior to the sewing, non-woven filler filaments may be deposited upon the rack filaments so that the sewn filaments may sew the filler filaments to the rack filament.

The sewing operation is performed at a sewing station disposed along the predetermined path, around which the loops are moved endlessly. The sewing operation may be performed automatically by sewing back and forth transversely of the rack filaments and advancing loops of the rack filament a predetermined amount after each traverse. With the rack filament wound on the rolls, the loops may be advanced by driving one of the rolls, thus advancing the loops over the predetermined path. The fabric is thus formed as the loops are moved around the predetermined path. The sewing is continued until the first row of stitches returns to the sewing station. At this point, the sewing operation is completed.

For most applications of the sewn fabric, it is necessary that it then be stabilized. Stabilization may be effected in various ways, depending upon the materials of which the fabric is made and upon the particular use to which it is to be put. The stabilization may usually be effected by heat treatment or by adding a bonding agent or by both. The sewn fabric thus formed may be finished on the same rack by continuing to advance the fabric about the predetermined path past at least one other station. At one ted States Patent 3,459,612 Patented Aug. 5, 1969 ice station the fabric passes through an oven. This oven is turned on as the fabric advances and is gradually brought up to a predetermined temperature as the fabric passes endlessly through it. It is preferred that the fabric pass several times through the oven before the oven reaches the predetermined temperature in order that the heat treatment he gradual. The heat treatment may shrink the fabric, and it is preferable that this shrinking be gradual in order that it may be more uniform and without placing great local stresses upon the fabric in the process.

For many purposes, it is necessary that the fabric be made a predetermined length. For such purposes and others, it is helpful to control the amount the fabric shrinks with heat. This may be achieved by controlling the temperature or by holding the rack in a predetermined fixed position to define a path of predetermined length. Under such circumstances, the heat shrinking does not shrink the fabric to a length less than this predetermined length. The temperature to which the fabric is heated depends upon the particular materials of which the fabric is made. As it is usually desirable to limit the amount of subsequent heat shrinkage, it is desirable that the fabric be heated to a temperature as high as it is likely to experience in use in order that it not shrink further in use. Preferably, the fabric is heated to a temperature just below that which would damage the fabric, as by melting it, for it is then certain that it will never be used at a hotter temperature, since any hotter temperature would destroy the fabric anyway.

For most purposes, it is desirable that the fabric be chemically stabilized as well as heat stabilized. To this end, some bonding agent may be applied to the fabric, which bonding agent is then cured, preferably by running the fabric through the same oven as used in the heat treating.

It is therefore a primary object of the present invention to provide a method and apparatus for making fabric by sewing loops of rack filaments together with sewn filaments to form an endless mesh fabric. Another object of the invention is to provide method and apparatus for making such a fabric in which non-woven filler filaments are sewn to the rack filaments by sewn filaments. Still another object of the invention is to provide a method and apparatus for disposing a plurality of loops of rack filament upon a rack, sewing the rack filaments together with sewn filaments transversely of the rack filaments while the rack filaments are on the rack, and stabilizing the sewn fabric thus produced while the fabric remains upon the rack. Further objects and advantages of the present invention will become apparent from consideration of the following description taken in conjunction with the following drawings wherein:

FIGURE 1 is a perspective view of a rack for forming fabrics by sewing according to the present invention, illustrating in particular the winding on of a single continuous rack filament to form a plurality of laterally disposed loops;

FIGURE 2 is a side elevation of the apparatus as shown in FIGURE 1;

FIGURE 3 is a partial end elevation of the apparatus shown in FIGURE 1, illustrating in particular the tying off of the filament upon completion of the winding on;

FIGURE 4 is a perspective view of the rack shown in FIGURE 1, illustrating the formation of an endless fabric by sewing transversely of the loops of rack filament;

FIGURE 5 is a side elevation of the apparatus as shown in FIGURE 4;

FIGURE 6 is an enlarged sectional view of the comb illustrated in FIGURE 5;

FIGURE 7 is an enlarged side elevation of the sewing means shown in FIGURE 4;

FIGURE 8 is an enlarged view, partly in section, of the driving mechanism for the sewing means shown in FIGURE 7;

FIGURE 9 is a diagrammatic illustration of the electrical circuitry for controlling the operation of the driving mechanism shown in FIGURE 8;

FIGURE 10 is a side elevation of the rack shown in FIGURE 1, illustrating in particular the stabilization of the sewn fabric;

FIGURE 11 is an enlarged sectional view of the oven illustrated in FIGURE 10 taken along line 1111 of FIGURE 12; and

FIGURE 12 is an enlarged sectional view of the oven illustrated in FIGURE 10 taken along line 12-12 of FIGURE 11.

In general, the fabrication of endless sewn fabric in accordance with the present invention involves three successive operations: (1) the disposition of loops of rack filament upon a rack; (2) the sewing together of the loops of rack filament; and (3) the finishing or stabilizing of the sewn fabric thus produced. FIGURES 1-3 illustrate the first operation. FIGURES 4-9 illustrate the second operation. FIGURES 10-12 illustrate the third operation.

THE RACK In FIGURE 1 there is illustrated a rack 11 upon which a single continuous filament 13 is wound. As shown, the rack 11 includes two spaced frames 15 and 17 having means for mounting elongated support members in the form of rolls thereon. The frame 15 comprises a pair of spaced parallel uprights 19 and 21. The uprights 19 and 21 may be constructed of wood or other suitable material. To maintain a spaced relation between the uprights a cross support member 23 is secured thereto. The lower ends of the uprights 19 and 21 are each secured to a respective fixed longitudinal member 25, 27 by a single bolt 29 which passes through the end of the upright and through the fixed member, thereby permitting limited rotary movement of the uprights about the fixed members. The fixed members 25 and 27 may be secured to the floor. To prevent the frame 15 from falling over as the apparatus is being placed in operation, support chains 31 are provided which are secured between the uprights 19 and 21 and the fixed members 25 and 27 as shown in FIGURE 1.

Journaled in the upright members and positioned slightly below the upper ends thereof is a stretch roll 33 which may be coupled by means of a pulley 34 and suitable belts 36 to a motor 35. The roll 33 is provided at one end thereof with a crowned portion 37 for receiving a flat belt 39.

Serving to guide the filament over the cross member 23 is an eye 40 through which the filament is passed and a rod bearing 42 providing a low friction surface for the filament as it passes over the member 23. To permit adjustment of the tension of the filament, a tension adjusting means 44 is provided as illustrated more particularly in FIGURE 3 and described in greater detail below.

Serving to maintain desired spacing between adjacent turns of the continuous filament 13 is a comb 41 which is detachably secured to the frame 15 and positioned so that the filament turns can fall in the recesses 43 between the teeth of the comb 41 (see FIGURE 3).

The rear frame 17 includes spaced uprights 45 and 46 the lower ends of which are secured to fixed members 47 which in turn may be secured to the floor. The uprights 45 and 46 should be secured against motion as by bracing them or aflixing their upper ends to the ceiling. Rotatably mounted upon the uprights 45 and 46 are three rolls, an upper roll 49, an intermediate roll 51 and a lower roll 53. As illustrated in FIGURE 1 the axle of the intermediate roll 51 has afiixed thereto a pulley 55 for rotatably driving the roll 51 in a manner to be hereinafter more clearly described.

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The support rolls 33, 49, 51 and 53 generally define an endless path over which the loops of rack filament 13 are disposed in performing the first operation of disposing loops of rack filament 13 on the rack 11 and over which the rack filaments 13 are moved in the subsequent sewing and stabilizing operations. The stretch roll 33 is mounted for movement about the bolts 29 in order to adjust the length of the path and maintain proper tension in the rack filament 13 after it has been disposed on the rack 11. To provide a means for adjusting the position of the stretch roll 33 and the tension Within the filament 13, a tensioning means 57 is provided. In the illustrated embodiment, the tensioning means 57 comprises a pair of upright support members 59, the lowermost ends of which are rigidly secured to the fixed members 25 and 27. The support members 59 should be secured against movement as by appropriate bracing or by securing their upper ends to a ceiling. The frame 15 is provided with two bolts 61 positioned opposite hooks 63 provided upon the uprights 59. Secured between the bolts 61 and hooks 63 are chains 65 each having a turnbuckle 67 serving as a means for adjusting the distance between the fixed uprights 59 and respective movable uprights 19 and 21 and for placing proper tension in. the wound filament 13.

It is generally desirable that the finished fabric be of uniform length across its entire width. To this end, it is preferable that the lengths of the paths taken by the respective filaments all be substantially the same. The uprights 19 and 21 are therefore adjusted to provide equal path lengths at both ends of the roll 33. This adjustment may be by any suitable method as by trial and error or accurate measurement. This adjustment may be effected by use of the turnbuckles 67. At the same time, it is contemplated that the tension in the loops of filament 13 or in the sewn fabric may be adjusted from time to time during the fabrication process. Since this adjustment of tension is also effected by use of the turnbuckles 67, and since the turnbuckles 67 are independently adjusted, means is provided for assuring that the rack re mains square during such adjustment of the turnbuckles 67.

As illustrated, a simple means for keeping the rack square comprises a pair of cords 68 each attached at one end to a respective one of uprights 19, 21 as by eyes 69, The other ends of the cords 68 are passed over guides 71) to an indicating means 71, which may comprise a carpenters level 72 disposed on a support 73 in turn supported at each end by a respective one of cords 68. With the rack initially square, the cords 68 are tied at such lengths that the level 72 is horizontal. Then any relative difference in the distances between the uppermost ends of the uprights 19 and 21 and the respective support members 59 will be readily detected by the indicating means 71. If the respective turnbuckles 67 are adjusted while keeping the level 72 horizontal, the rack 11 is kept square.

FILAMENT WINDING The first operation, that of disposing loops of rack filament 13 in predetermined laterally spaced relation upon the rack 11, may now be described in a preferred embodiment by reference to FIGURES 1 to 3. The fila ment 13 may be drawn from a spool or bobbin 75. The filament may be made of any of a number of materials used in textiles. For example, it may be made of synthetic fibers such as polyester fibers sold under the trademark Dacron. However, many other materials such as other synthetic fibers, natural fibers, metal and even paper can be used, depending upon the use to which the finished fabric is to be put. The number of loops and the size of the filament 13 depends upon the material of which the filament 13 is made as well as upon the desired properties of the finished fabric. The rack filament 13 provides strength to the finished fabric and must therefore be large enough for the purpose; at the same time it must not diminish other desirable properties of the fabric, such as its permeability. For making one type of filter fabric, it has been found suitable to use a Dacron filament of 220 denier with 16 loops per inch.

The free end of the rack filament is passed from the storage spool 75 through the eye 41 and the adjustable tension means 44 and over the low friction bearing 42. The free end of the rack filament 13 is then secured to the belt 39 as by tying the free end of the rack filament 13 to the belt 39.

The belt 39 is disposed on the rolls 33, 49, 53 and 51 in the path along which it is desired to dispose loops of rack filament 13. The belt may be of any suitable flexible material and may even be a turn of the rack filament 13 itself. That is, rather than tying the free end of the filament 13 to a separate belt 39, the free end may be hand carried over a complete loop, following the desired path, and may then be tied to itself, forming a closed loop comprising the belt 39. The motor 35 is actuated to drive the roll 33 which in turn drives the belt 39 about the path defined by the rolls 33, 49, 53 and 51.

Each time the belt makes a complete turn around the predetermined path, a loop of rack filament 13 is disposed on the rack in this same path. The comb 41 serves as guide means for guiding successive turns of the rack filament 13 into predetermined spaced relation. As illustrated, each turn of the belt deposits a turn of filament 13 near the belt. This turn may then be deposited in the empty recess 43 nearest the far end of the comb. This turn may be hand carried to the proper recess or mechanical means may be provided. Alternatively, the comb 41 may be movably mounted and driven in synchronism with the belt 39 so that the proper recess is disposed at the belt 39 to receive each turn of rack filament as it is wound out, moving ultimately to its final position as shown in FIGURE 3. As another alternative, the comb 41 may be made in the form of a screw turned in synchronism with the belt 39; each successive turn may then fall in the groove 43 between screw threads nearest the belt 39 and drawn longitudinally of the roll 33 to the same final position, when the screw is stopped.

Irrespective of how the filament 13 is placed in the recesses 43, successive turns of the filament are moved longitudinally of the roll 33 into predetermined substantially parallel laterally spaced relation on the rack 11. As the turns move through the predetermined path around the rolls 33, 49, 51 and 53, they naturally assume substantially parallel relations with a lateral distribution determined by the relative disposition of the recesses 43.

When all of the desired number of turns of rack filament 13 have been wound on the rack 11, the two ends of the filament may be cut and tied together as shown in FIGURE 3. The end cut from the belt 39 is brought down from the roll 33 and passed over a pulley 77 mounted on the cross piece 23. The end cut from the spool 75 is brought up and around the roll 33, then down over a pulley 79. The two ends may then be tied into a knot 81.

If the loops of rack filament 13 are not substantially parallel, the roll 33 may be driven one way or the other or preferably back and forth for a number of turns. The loops will tend to assume a disposition more nearly parallel. Of course, the loops are never truly closed, and the continuous filament in fact gradually moves in a spiral toward one end or the other, the part that is thus wound off at one end of the roll 33, being returned by way of the pulleys 77 and 79 to the other end, where it is wound on. Movement of the loops also serves to equalize the tension in the loops. The loops are all laid down under comparable conditions, but because of friction, the tension is not necessarily the same in each loop. Further it may be desirable to modify the tension or change the length of the predetermined path. This may be achieved by adjusting the turnbuckles 67 and adding or removing a length of filament 13 at the knot 81. In any event, since there is but a single continuous filament, the tension is readily equalized by a few turns of the roll 33.

The rack 11 is thereby set up for the sewing operation. It is often desirable however to hold the loops of rack filament in the proper relationship during the sewing operation. To this end, additional combs may be inserted at appropriate locations around the predetermined path.

It may be noted that the diameter of the crowned portion 37 of the roll 33 is somewhat larger in diameter than the roll 33 itself. This drives the belt 39 and hence the free end of the filament 13 somewhat faster than the roll 33 advances the filament 13 from the spool 75. This keeps the filament 13 tight as it is wound on, thus avoiding slack that might entangle the filament. The tension means 44 also serves to keep the filament 13 taut. The tension means 44 may as shown, comprise a pair of washers 83 between which the filament 13 is drawn from the spool 75. The friction thus created keeps the filament taut. The amount of friction is determined by the compression in a spring 85 which is urging the washers 83 together. The spring compression may be adjusted by a nut 87 mounted on a screw 89, thus controlling the tension in the filament 13 as it is Wound on the rack.

SEWING The sewing operation will now be described, making particular reference to FIGURES 4 to 9. The sewing is performed on the same rack 11, with certain modifications in the set up. The belt 39 has been removed, and the drive belt 36 driving the pulley 34 has been disconnected. For sewing, the rack filaments are advanced by driving the roll 51. As shown, a drive motor is coupled through a magnetic clutch 97 to a gear box 96 which in turn is connected by a drive chain 98 to the roll 51. Although not shown in FIGURES 1 and 2 because not used in winding the filament 13 on the rack 11, this driving apparatus could as well be physically present, although disconnected, during the winding on operation. Alternatively, it is within the scope of this invention to modify the apparatus to utilize the same driving apparatus for both the winding on and the sewing operations.

Although it is within the scope of the invention to fabricate a sewn mesh fabric without additional filler material, it is generally desired to make the fabric to include such filler. The filler acts to provide certain qualities to the finished fabric as may be desired for particular uses. The filler may be made of various materials and in various forms. A filler suitable as filler for filter fabrics has been found to be filler formed of randomly disposed synthetic fibers such as polyester fibers sold under the trademark Dacron. Such fibers are sold in nonwoven sheet form in which the fibers are bonded together. One useful form is sold under the trademark Spunbonded and comes in various thicknesses thereby permitting selection of properties for the fabric, such as it porosity or permeability. A size found useful for making filter fabric is sold as Style 240.

Filler material 99 is preferably supplied from a roll 101 which is rotatably mounted upon a frame 102 comprising uprights 103 which are secured to the fixed mem bers 25 and 27. The filler sheet 99 is directed over a pair of guide bars 104 also secured upon the frame 102. These guide the sheet 99 to the sewing station where it is to be sewn to the rack filaments 13.

The rack filaments 13 are themselves guided to the sewing station by a guide bar 105 and a comb 106. The bar 105 and the comb 106 are removably mounted upon the frame 102 and are secured in place at the positions indicated after the loops of rack filament 13 have been disposed upon the rack 11 in the manner described above. The comb 106 is supported on the frame 102 by a pair of arms 197. As shown best in FIGURE 6, the comb 106 comprises an upper comb bar 108 and a lower comb bar 109, between which extend comb teeth 110. The rack filament 13 extends between the upper comb bar 108 and a lower comb bar 109 with individual loops of rack filament 13 being captured between respective successive comb teeth 110. The filler 99' rides on the underside of the lower comb bar 109. The loops of rack filament 13 and the filler are thus directed to the sewing station in the desired relationship.

:It is desired that the filler 99 be delivered smooth and unwrinkled. To this end a retarding force is applied to the filler '99 as it leaves the roll 101. Thus, when the filler is pulled away in the course of fabrication of the fabric, the filler sheet 99 is stretched fiat. The retarding force may be derived from a brake 111 which applies retarding torque to the axle 112 of the roll 101. The brake 111 may, as shown, comprise a brake band 113, urged against the axle 112 by a spring 114. The tension on the spring and hence the braking force is adjusted by a turnbuckle 115. A relatively heavy rod 116 may be floated on the filler sheet 99 to aid in keeping it smooth and unwrinkled.

To start the sewing operation, the end of the filler sheet 99 may be hand carried to the sewing station at which is disposed a sewing means 117. The sewing means 117 is then operated to sew the filler 99 to the loops of rack filament 13. The operation may then proceed automatically.

As illustrated in greater detail in FIGURE 7, the sewing means 117 comprises a support 118 for supporting a sewing machine 119' for movement transversely across the rack filaments 13 in a reciprocating manner. The sewing machine 119 may be of standard construction, having a sewing head 121 and a sewing bed 122 with a throat therebetween sufficient to permit the sewing head 121 to traverse the rack filaments 13. The sewing machine 119 is mounted upon a slidable support member 123 and bearing rollers 124 to facilitate movement along the path defined by the support 118.

The sewing means 117 may be permanently mounted at the sewing station, or it may, as shown, be mounted on rollers 125 and roller into operating position after the filament 13 has been wound on the rack 11 and then locked in position. The sewing machine 119 is caused to move back and forth across the support 118 by the action of a screw 126 which is driven in a manner described in greater detail below in connection with FIGURES 8 and 9. The screw 126 is driven first one way and then the other. It engages the slidable member 123 to drive the sewing machine 119 mounted thereon.

The position of the sewing machine 119 as it reaches the longitudinal edges of the rack filaments 13 is sensed by a pair of limit switches 127, 129. Both limit switches may be double pole, double throw microswitches mounted upon the support 118. The microswitches 127 and 129 may, as shown, be actuated by the support 123 which is driven back and forth with the sewing machine 119 as shown in FIGURE 7. Limit switch 127 senses when the sewing machine 119 has reached the right limit, and limit switch 129 senses when the sewing machine 119 has reached the left limit of its desired travel.

The sewing machine 119 is driven through a gear train 133 by a drive shaft 135 journaled in a bearing 137. A driving mechanism 138 is mounted on a pedestal 139, which pedestal supports the support 118 The driving mechanism is shown in greater detail in FIGURE 8. The motive power is developed by an electric motor 140 which is coupled by a belt 141 to a pulley 142. mounted on a shaft 143. The shaft 143 is coupled to the drive shaft 135. Preferably the drive shaft 135 is made square, and the shaft 143 is made with a mating square opening therethrough. This provides positive action for rotating the drive shaft 135 while permitting it to slide longitudinally as the sewing machine 119 is reciprocated. The shaft 143 is journaled in bearings 144 and 145. A pinion gear 147 is rigidly mounted on the shaft 143 for driving machine traversing mechanism 149.

The pinion gear 147 is meshed with a spur gear 151 for driving a shaft 153 rotatably mounted in bearings 155. Positioned below the shaft 153 and rotatably mounted in bearings 157 is a shaft 159. Mounted for selective rotation about the shaft 159 is a right advance clutch 161 coupled to a pulley 163 driven through a belt 164 by a pulley 165 mounted on the shaft 153. Also mounted for selective rotation about the shaft 159 is a left advance clutch 169 coupled to a gear 171 engaged with a gear 173 mounted upon the shaft 153. Provided upon one end of the shaft 159 is a gear 175 which is engaged with a similar gear 177 mounted upon the advance screw 126. The advance screw 126 is threaded through the support member 123 so that rotary movement of the screw 126 causes the member 123 to traverse the support 118.

The shaft 143 is driven by the motor 140 in the direction indicated by the arrow A. This of course drives the shaft 153 in the opposite direction as indicated by the arrow B. This in turn drives the pulley 163 in the same direction as indicated by the arrow C, while at the same time driving the gear 171 in the opposite direction as indicated by the arrow D. The clutches 161, 169, which may be conventional electrically energized magnetically operated clutches, selectively drivingly engage either the pulley 163 or the gear 171 with the shaft 159, thus driving the shaft 159 one way or the other. With the clutch 161 engaged, the shaft 159 turns in the direction indicated by the arrow C, thus turning the screw 126 to advance the support 123 and the sewing machine 119 to the right as shown in FIGURE 8. Similarly, with the clutch 169 engaged, the shaft 159 turns in the direction indicated by the arrow D, thus turning the screw 126 to move the support 123 and the sewing machine 119 to the left. The operation of the clutches is controlled by a control system 181, which may be in the form illustrated in FIGURE 9.

Referring to FIGURE 9, the control system 181 includes the double pole, double throw microswitches 127 and 129, which are the sensing elements for the control system. The switches 127, 129 are shown in their normal condition into which they are biased when the sewing machine 119 is between the limits. Switch 127 includes a pair of movable contacts 182, 183, each connected at all times to a power supply 184. Switch 129 includes a pair of movable contacts 185, 186 also connected at all times to the power supply 184.

Contacts 182 and 185 normally engage fixed contacts 187 and 188, respectively, these contacts 187, 188 being open circuited. When switch 127 is operated, the movable contact 182 is moved into contact with a fixed contact 189. Similarly, when switch 129 is operated, the movable contact 185 is moved into contact with a fixed contact 190. The contacts 189, 190 are connected to the actuating coil 191 of a time delay relay 192 of the double pole, double throw type. Thus the relay 192 is actuated when either of the limit switches 127, 129 is operated.

Contact 183 normally engages a fixed contact 193, and contact 186 normally engages a fixed contact 194. When switch 127 is operated, the movable contact 183 is moved into contact with a fixed contact 195. Similarly, when switch 129 is operated, the movable contact 185 is moved into contact with a fixed contact 196. Contacts 195, 196 are both connected to a movable contact 197 of the relay 192. The other movable contact 198 of the relay 192 is connected to the power supply 184.

Time delay relay 192 is biased so that contact 197 normally engages a fixed contact 199 and contact 198 normally engages a fixed contact 200. Contact 199 is connected to the rack filament advance clutch 97, and contact 200 is open circuited. When the time delay relay 192 operates, contact 197 moves to contact a fixed contact 201, which is open circuited, and contact 198 moves to contact a fixed contact 202, which is connected to the actuating coil 203 of an alternate pulse relay 204, which is also of the double pole, double throw type.

The relay 204 includes two movable contacts 205 and 206. Contact 205 is connected to the right advance clutch 161, and contact 206 is connected to the left advance clutch 169. The operation of the relay 204 moves the contact 205 from one to the other of fixed contacts 207 and 208, at the same time moving the contact 206 from one to the other of fixed contacts 209 and 210. Contacts 207 and 210 are open circuited. Contact 208 is connected to contact 193, and contact 209 is connected to contact 194. Operation of the relay 204 thus alternately open circuits one or the other of the advance clutches 161, 169. With the switches and relays in the positions shown in FIGURE 9, the sewing machine will be advanced to the right.

For purposes of describing the operation of the traversing mechanism 149 and the control system 181, it will be assumed that the positions of the switches and relays are as shown in FIGURE 9 and that the sewing machine 119 is moving along the support 118 towards the right as viewed in FIGURE 7. As the sewing machine 119 is traversing its path along the support 118, the filament advance clutch 97 is disengaged and the loops of rack filament 13 are stationary upon the rack 11. The pulley 142 is driven, causing the drive shaft 135 to rotate, thereby actuating the sewing machine 119 through the gear train 133. As shown in FIGURE 9, the right advance clutch 161 is engaged, thereby coupling the pulley 163 to the shaft 159 and advancing the sewing machine 119 to the right along the support 118.

When the sewing machine 119 reaches its right limit of travel, the right microswitch 127 is operated, disconnecting the movable terminal 183 from the fixed terminal 193, thereby de-energizing the right advance clutch 161, preventing further advance of the machine 119. At the same time, the movable contact 183 is moved to engage contact 195, thus energizing the rack filament advance clutch 97. Energization of the rack filament advance clutch 97 causes the rack filament 13 to advance along the path of the rack 11. Also at the same time, the operation of the switch 127 moves the movable contact 182 into contact with the contact 189, thereby energizing the time delay relay 192. However, as is conventional with time delay relays, the relay 192 remains open for a predetermined interval of time.

After the predetermined interval has elapsed, the relay 192 will pull in, causing the movable terminal 197 to break with the terminal 199 and thereby de-energizing the clutch 97 and stopping the advance of the loops of rack filament 13. The loops of filament 13 are thus advanced by a predetermined increment along the rack 11. As the relay 192 pulls in, it moves the movable contact 198 into contact with contact 202, thus actuating the alternate pulse relay 204. As is conventional with alternating pulse relays, each actuation causes it to reverse states. Hence, under the condition assumed, the actuation of the relay 204- moves the contact 205 away from contact 208 and moves the contact 206 into contact with the contact 209.

Since the microswitch 129 is in its normal condition, the engaging of contact 206 with contact 209 energizes the left advance clutch 169, thereby coupling the gear 171 with the shaft 159 and advancing the sewing machine 119 to the left. As the sewing machine moves left, the microswitch 127 returns to its normal state. This moves contact 182 out of engagement with the contact 189, thus deenergizing the relay 192, which returns to its normal state. Although this brings contact 197 into engagement with contact 199, the rack filament advance clutch 97 is not energized because the contact 183 is disengaged from contact 195 upon release of the microswitch 127. Although this at the same time engages contacts 183 and 193, the right advance clutch 161 is not energized because the contact 205 was earlier disengaged from contact 208.

The control system 181 is then back in its normal condition, with all connections as shown in FIGURE 9 except for the alternate pulse relay 204, which is in its alternate state. The sewing machine 119 continues its advance to the left until the left limit microswitch 129 is actuated, whereupon a series of operations occurs corresponding to that described above upon actuation of the right limit microswitch 127. In this manner, the sewing machine 119 is caused to traverse the loops of rack filament 13, sewing parallel rows of stitches back and forth across the loops, thereby sewing the filler 99 thereto.

It may be noted that, with the arrangement illustrated and described, the sewing machine 119 is continually operated during the switching and reversing operation; however, if desired the stitching may be stopped while the rack filaments 13 are advanced along the rack 11.

The sewing operation may now be briefly described. After the rack filament 13 is disposed upon the rack 11, the comb 41 is removed and comb 106 put in place to guide the loops of rack filament 13 to the sewing station. The guide bar is inserted to guide the loops into the comb 106 at the desired angle. Proper tension is applied to the loops of rack filament 13 by adjusting the turnbuckles 67. A desirable tension has been found to be about 1.5 pounds per loop for a Dacron filament of 220 denier. The filler 99 is then withdrawn from the roll 101 and directed over guides 104 and under the comb 106 to the sewing station. The filler 99 is disposed against the loops of rack filament 13 on the bed 122 of the sewing machine 119.

The sewing machine 119 traverses back and forth across the loops of rack filament 13, sewing the filter 99 thereto, the loops of rack filament 13 and the filler 99 being advanced a predetermined amount after each traverse. This makes equally spaced substantially parallel rows of stitches. It may be necessary to pull the filler 99 along separately for a few rows, but thereafter they are readily pulled along by the rack filament 13.

The sewing machine 119 itself may have a conventional sewing head 121. It may make any of a variety of stitches including lock stitches and chain stitches. A single thread chain stitch has the advantage that it does not require a bobbin beneath the bed 122; such bobbins are almost necessarily small and therefore hold so little thread that the sewing operation must be stopped to replenish the thread in the bobbin. This makes completely automatic operation diificult. Any of a number of materials may be used for the sewn filaments, including those mentioned above for the rack filament 13. For making filter fabrics, it has been found suitable to use Dacron filaments of 220 denier for both the rack and the sewn filaments. With such rack filament 13 wound as above described at 16 loops per inch and with a filler of Spunbonded fibers, Style 240, the fabric was found to be suitable as a filter fabric when the sewn filaments were stitched in rows at 8 stitches per inch with the rows one-third inch apart.

The sewing operation may continue automatically until the sewn portion reaches the roll 33. At least by that point it is necessary to cut the filament 13 where it passes over the pulleys 77, 7-9 in order that the sewn fabric may pass over the roll 33. By the time the sewn fabric reaches the roll 33, the rack filament 13 is so tightly held by the sewn filaments that the tension in the rack filament 13 is not significantly altered by such cutting.

The sewing operation may then continue automatically until the sewn portion approaches the comb 106. The comb 106 is then removed and the sewing is continued automatically until a complete endless loop of fabric is formed. For stability it is usually desirable that the filler 99 be lapped for at least one row of stitches. The filler 99 may then be cut off the roll 101, and the sewn fabric is ready for the finishing operation.

STABILIZING The stabilizing operation will now be described, making particular reference to FIGURES 10-12. The stabilizing is likewise performed on the same rack 11. The apparatus illustrated is suitable for heat stabilization or stabilization by adding a bonding agent or by both. The sewing machine 119 may be taken away and the guide bar 105 removed. The turnbuckles 67 may then be adjusted, if necessary, to provide such tension in the chains 1 1 65 as will maintain proper tension in the sewn fabric (identified by the numeral 213) during the stabilizing operation and hold the length of the fabric 213 to the desired magnitude.

An oven 223 is assembled around the sewn fabric in the portion of its travel between rolls 53 and 49". It may be noted that the fabric 213 is travelling vertically upward from roll 53 to roll 49. This arrangement of the rolls 53 and 49 was made particularly for the stabilizing operation for reasons that will appear below.

The oven 223 comprises two rectangular concave sections 225 and 227 which mate to form a heating cavity about the mesh fabric 213 as it is passed therethrough. A spacer 229 is disposed along each lateral edge of the section 225; they act to seal the sides of the oven 223 while permitting the mesh fabric 213 to pass freely into the oven 223 at the bottom and out at the top.

Secured to the lower corners of the section 225 are angle channels 235 for positioning and receiving the section 227. The sections 225 and 227 may be held together by latches 236. Although the section 225 is not shown in FIGURES 1-5, it is ordinarily convenient to support the section 225 upon the uprights 45, 46 in permanent fashion. Brackets 237 and 238 are provided for this purpose. The brackets 237, 238 may he secured to the section 225 by suitable means such as by Welding and fastened to the uprights 45, 46 as by screws. All that is needed then to place the oven in operation is to place the cover section 227 in position, secure the latches 236, and turn on the heat.

The oven 223 may be heated by hot air supplied through an input conduit 239 from a source of hot air. Although not shown in the drawings, the source of hot air may be any of a number of commercial heater-blowers. The hot air may 'be distributed by a flow spreader 249 to provide an evenly distributed flow of hot air into the oven 223 through a transverse slot 241 which is cut through the wall of the section 225. As shown in FIG- URE 11, a downwardly projecting transverse vane 243 is secured to the wall of section 225 slightly above the slot 241, serving to deflect the hot air downwardly in the oven, rather than directly against the fabric 213.

To facilitate proper distribution of temperature within the oven 223, air is exhausted therefrom through an elongated exhaust slot 245 out through the lower portion of the wall of the section 225. A cowl 247 is provided upon the section 225 in communication with the exhaust slot 245 to facilitate removal of air from the oven 223. The air may then be exhausted to the outside atmosphere through an exhaust duct 248.

The sewn fabric 213 may be advanced through the oven 223 by the same motor 95 as is used in the sewing operation. The speed of movement is ordinarily desired to be decidedly different, hence requiring a change of gearing, a variable speed motor or some other means for driving the fabric 213 at the different speed. In operation, it is generally preferable that the fabric be continuously advanced at a substantially constant rate. This includes, however, the periodic advance in relatively small increments, as may be achieved, for example, by pulsing the operation of the motor 95. The fabric 213 is advanced vertically upward through the oven 223. The preferred rate of advance depends among other things upon the material of which the fabric 213 is made, the temperature of the oven, the dimensions of the oven and the intended end uses of the fabric. For example, with a fabric 213 made of polyester fibers sold under the trademark Dacron heated in an oven 223 about three feet long between inlet 241 and outlet 245 and about four feet long altogether with a maximum temperature at the inlet of about 380 F., heat treating with the fabric advancing at about inches per minute produced a satisfactory filter fabric.

It is preferable that the fabric 213 be started through the oven 223 when the oven is cold, and then to begin supplying hot air to heat the fabric gradually. It is preferred that the fabric pass entirely through the oven 223 several times as the oven 223 is brought to a predetermined tomperature. This is 'because the heat treatment produces dimensional changes in the fabric 213, in particular, shrinking it, and the ultimate fabric is of more uniform quality if the shrinking is gradual. Sudden shrinking often is uneven and places local stresses on different parts of the fabric; this may warp the fabric or weaken it.

The oven 223 is heated by introducing hot air through the inlet 241 and passing it downwardly counter to the direction of movement of the fabric 213. The air is naturally cooled as it travels to the outlet 245. This assures that the hottest part of the oven is toward the end of the oven last reached by the fabric, again causing a gradual heating and hence gradual shrinking of the fabric.

The preferred temperature of the heated air delivered to the oven depends upon a number of factors such as the temperatures the fabric is to be exposed to during use, and the temperatures that would damage the fabric. As noted above it is, in general, preferable to heat the fabric to as high a temperature as the fabric is likely to experience in use in order that it not shrink further while in use. On the other hand, the fabric should not be damaged by the heat. Synthetic fibers, for example, melt at excessive temperatures. Since the fabric cannot be used at temperatures that would destroy it, it is preferred that the fabric be heated to a temperature just below that which would damage it. To achieve such heating of the fabric, it is necessary that the incoming hot air be somewhat hotter than the desired fabric temperature because of the thermal inertia of the fabric, the motion of the fabric through the oven and the mixing of the incoming air with the cooler air already in the oven. Input air providing a maximum temperature of 380 F. has been found desirable in the example noted above, i.e., fabric made of polyester fibers sold under the trademark Dacron moving through the oven at a rate of 10 inches per minute.

Once the fabric 213 has been heated to the desired temperature, it has been heat stabilized and will not heatshrink further unless heated to a greater temperature. In the case of endless fabrics, it is frequently desirable that the finished fabric have certain dimensions, particularly in length. The chains 65 hold the fabric 213 to the desired length; therefore, except for such longitudinal shrinkage as is permitted by the tension members 65, the shrinkage of the fabric is in the cross direction. As an example, under the conditions mentioned in the preceding paragraph, a fabric 28 /2 inches wide shrunk to about 24 inches, while the length was held substantially constant at about 30 feet.

As noted above the fabric 213 is moved vertically up ward through the oven 223, and the hot air is introduced substantially uniformly across the oven 223 and driven downwardly counter to the movement of the fabric 213. This provides an even heat sweep, avoiding convection currents out the sides of the oven or the trapping of air in the center. The vertical disposition of the fabric avoids any catenary sagging of the fabric during the heat treatment which would heat set the fabric in an undesirable shape. It also avoids differential shrinkage occasioned by the different tensions introduced by the sagging of a horizontally disposed fabric. For many uses it is necessary that the fabric be substantially fiat; that is, its length should be the uniform all the way across.

It is ordinarily desirable to stabilize the fabric chemically as well as thermally, preferably after the heat stabilization. This may be performed with the same set-up. The only change required is means for adding the required chemical to the fabric. For this purpose a trough 251 may then be disposed around the roll 53 and partially filled with a bonding agent 252.

Any of a great number of bonding agents may be used, depending upon the material of which the sewn fabric is made and the use to which the fabric is to be put. Ordinarily, almost any resin commonly used for the purpose can be used. Epoxy resins have been found particularly suitable. Various silicone compounds are suitable. Polyurethane resins are suitable. Suitable bonding agents include those that encapculate the fibers and those that penetrate into the fibers. Continuing the example above, with rack filament 13, sewn filaments and filler 99 all made of Dacron fiber, an epoxy resin has been found suitable for making a filter fabric. Particularly for stabilizing fabrics for use as filters, the resin may be diluted, as by acetone, so that not so much bonding agent is applied as to close up the passages in the filter and render the filter ineffective. Indeed it is by controlling the dilution of the bonding agent before it is applied that the amount of bonding agent actually applied is controlled.

More particularly an epoxy resin sold under the trademark Resiweld, Formula No. 7004, diluted ten to one by acetone has proven satisfactory in bonding the fabric of the above example for making a filter fabric suitable for filtering papermill effluent. This very dilute solution applies sufiicient bonding agent to stabilize the fabric suitably without plugging the passages through the fabric which would make it unsuitable as a filter. It may also be noted that this particular bonding agent produces a well stabilized, relatively stiff finished fabric. The stiffness makes the fabric easier to handle for many uses.

For other uses, it may be more desirable to have a more flexible fabric that may be distorted without wrinkling. Silicone compounds have been found suitable for stabilizing such fabrics. Multiple treatments with the same or different bonding agents may be used to achieve different properties in the finished fabric, such as combined stiffness and abrasion resistance.

The bonding agent is added to the fabric 213 as the fabric is driven through the bonding agent 252 in the trough 251 by the motor 95. The bonding agent 252 saturates the fabric 213, and as the fabric 213 is driven upwardly, the excess bonding agent flows back down the the fabric into the trough 251. Although many bonding agents cure in ambient air, it is usually desirable to cure them at high temperatures. This is particularly true where the bonding agent contains a solvent that must be driven off, for the solvent is more quickly evaporated at high temperatures. The heat curing may be effected in the oven 223 by driving the fabric 213 therethrough in the same fashion as in the heat stabilizing operation.

Again it is desirable that th heat treatment be performed while the fabric 213 is moving vertically. In addition to avoiding sagging occasioned by a catenary suspension which might result in stabilizing the fabric in an uneven condition while there was differential stretching of the loops of rack filament 13, the vertical disposition keeps the uncured bonding agent from dripping anywhere except back into the trough 251. In particular, it keeps the oven clean so that the fabric may be freely drawn through. In this connection it may be noted that the roll 53 is preferably coated with some phobic material such as the polymer of tetrafluoroethylene sold under the trademark Teflon in order that it remain free of the bonding agent.

It is also preferred that the bonding agent be substantially cured before it leaves the oven 223 so that it will adhere to the roll 49 or anything else after leaving the oven 223. For the quickest curing, the fabric 213 should be heated as hot as possible without damaging it. For the example given, an oven temperature of 380 F. is suitable, as it was during the heat stabilizing operation. Further the bonding agent is sufficiently cured and the solvent carried away when the fabric is driven at the rate of inches per minute, even when the bonding agent as applied is very much diluted by the solvent.

It is desirable that the bonding agent 252 be applied evenly to the fabric 213. To this end, the trough 251 is removed somewhat prior to the passage of the last of the fabric to which the bonding agent is to be applied. The excess bonding agent in the preceding portion of the fabric then drips down to treat the last portion without applying excess bonding agent to fabric already treated the first time around.

Although this treatment is often sufficient to cure the bonding agent, it is sometimes necessary to cure the bonding agent longer to be certain that the bonding agent is not only dry to the touch but is actually cured down into the fibers of the fabric. This may be achieved by passing the fabric through the oven one or more additional turns.

Upon completion of the stabilizing operation, the oven cover 227 may be removed and the rolls 33, 49, 53 disengaged from their mountings at one end to permit removal of the finished fabric 213 from the rack 11. The rack may then be set up again and the process repeated to produce another endless fabric.

Briefly summarizing the operation of the preferred embodiment of the invention as described above to produce the fabric of the particular example given:

(1) A continuous Dacron filament of 220 denier was wound upon the rack 11 by pulling the free end repeatedly around a predetermined closed path defined by a plurality of parallel rolls mounted in fixed spaced relationship to form the rack 11, thereby depositing successive turns of rack filament upon the rack, and by guiding the successive turns from their place of deposit into predetermined substantially parallel laterally spaced relation on the rack at 16 turns per inch.

(2) A style 240 Spunbonded sheet of Dacron fibers was deposited upon the underside of the turns of rack filament and sewn thereto by parallel rows of stitches of sewn Dacron filaments of 220 denier, the stitches being 8 to the inch and the rows one-third inch apart, the sewing being performed transversely of the turns of rack filament.

(3) The sewn fabric 213 was then gradually heated by passing it at 10 inches per minute vertically through the oven 223 as the oven was gradually brought up to a maximum temperature of about 380 F., thereby heat shrinking the fabric so that the fabric was thereafter temperature stable, at least up to the temperature to which it was :heated. Epoxy resin of Resiweld Formula 7004 diluted ten to one by acetone was then applied at the roll 53 to saturate the sewn fabric. The solvent was evaporated and the resin was cured by passing the fabric vertically at the rate of 10 inches per minute through approximately four feet of oven 223 heated to a maximum temperature of 380 F., the fabric being passed twice through the oven after the application of the bonding agent.

This produced a filter cloth suitable for filtering solids from the effluent of a papermill.

Although specific embodiments of this invention have been herein shown and described, it will be understood that details of the construction shown may be altered without departing from the spirit of this invention as defined by the following claims.

For example, a further control on the amount of bonding agent 252 added to the fabric 213 may be achieved by adding blowers between the treating station and the curing station and blowing off excess bonding agent. This also serves to keep the fabric open and of relatively uniform permeability.

The invention may be utilized to make a number of different fabrics by sewing, making them of a number of different materials for a number of different end uses. In particular, it may be utilized for making fabrics like those described in the aforesaid Lee application Ser. No. 431,- 030, now abandoned.

What is claimed is:

1. A method of manufacturing an endless mesh fabric comprising the steps of supporting a plurality of loops of rack filament in spaced relation upon a plurality of elongated support members mounted in fixed spaced relation to form a rack, applying tension to said loops on said rack, moving said loops endlessly around a predetermined closed path defined by said members to move successive portions of said loops past a station, and at said station sewing transversely of said loops of rack filament as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric while maintaining said loops in tension on said rack.

2. A method of manufacturing an endless mesh fabric comprising the steps of supporting a plurality of loops of rack filament in spaced relation upon a plurality of elongated support members mounted in fixed spaced relation to form a rack, said members defining a predetermined closed path of said predetermined length over which each of said loops extends coextensively, applying tension to said loops on said rack, moving said loops endlessly around said predetermined closed path to move successive portions of said loops past a station, and at said station sewing transversely of said loops of rack filament as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric of substantially said predetermined length while maintaining said loops in tension on said rack.

3. A method of manufacturing an endless mesh fabric comprising the steps of supporting a plurality of loops of a continuous rack filament wound in spaced relation upon a plurality of elongated support members mounted in fixed spaced relation to form a rack, applying equal tension to each of said loops on said rack, moving said loops endlessly around a predetermined closed path defined by said members to move successive portions of said loops past a station, and at said station sewing transversely of said loops of rack filament as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric while maintaining said loops in tension on said rack.

4. A method of manufacturing an endless mesh fabric comprising the steps of supporting a plurality of loops of rack filament in spaced relation upon a plurality of elongated support members mounted in fixed spaced relation to form a rack, applying equal tension to each of said loops on said rack, moving said loops endlessly around a predetermined closed path defined by said members to move successive portions of said loops past first and second stations, at said first station depositing non-woven filler filaments on said loops of rack filament, and at said second station sewing transversely of said loops of rack filament as successive portions thereof are moved past to sew said loops to said filler filaments to form an endless mesh fabric while maintaining said loops in tension on said rack.

5. An apparatus for the manufacture of endless mesh fabric comprising a rack including a plurality of elongated members mounted in fixed relationship to each other for receiving a plurality of loops of rack filament in spaced relation thereupon and supporting said loops for endless movement transversely of said members around a predetermined closed path, tensioning means associated with one of said members for applying tension to the loops upon said rack, means for moving the loops about said path to move successive portions of said loops past a station, and sewing means at said station for sewing transversely of said loops as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric.

6. An apparatus for the manufacture of continuous mesh fabric comprising a rack including a plurality of elongated members mounted in fixed relationship to each other to define a predetermined closed path of predetermined length for receiving a plurality of loops of rack filament in spaced relation thereupon and supporting said loops for endless movement transversely of said members around said predetermined closed path, tensioning means associated with one of said members for applying tension to the loops upon said rack, means for moving the loops about said path to move successive portions of said loops past a station, and sewing means at said station for sewing transversely of said loops as successive portions thereof are moved past to sew said loops together to form a continuous mesh fabric of substantially said predetermined length.

7. An apparaus for the manufacture of endless mesh fabric comprising a rack including a plurality of elongated members mounted in fixed relationship to each other for receiving a plurality of loops of rack filament in spaced relation thereupon and supporting said loops for endless movement transversely of said members around a predetermined closed path, tensioning means associated with one of said members for applying tension to each of the loops upon said rack, means for moving the loops about said path to move successive portions of said loops past first and second station, means at said first station for depositing non-woven filler filaments on said loops of rack filament, and sewing means at said second station for sewing transversely of said loops as successive portions thereof are moved past to sew said loops to said filler filaments to form an endless mesh fabric.

8. An apparatus for the manufacture of endless mesh fabric comprising a rack including a plurality of elongated members mounted in fixed relationship to each other for receiving a plurality of loops of a continuous rack filament in spaced relation thereupon and supporting said loops for endless movement transversely of said members around a predetermined closed path, tensioning means associated with one of said members for applying equal tension to each of the loops upon said rack, means for moving the loops about said path to move successive portions of said loops past a station, and sewing means at said station for sewing transversely of said loops as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric.

9. A method of manufacturing an endless mesh fabric comprising the steps of supporting a plurality of loops of rack filament in spaced relation upon a plurality of elon gated support members mounted in fixed spaced relation to form a rack, moving said loops endlessly around a predetermined closed path defined by said members to move successive portions of said loops past first and second stations, at said first station sewing transversely of said loops of rack filament as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric, and thereafter at said second station stabilizing successive portions of said fabric as they are moved past.

10. A method according to claim 9 wherein tension is applied to the loops to maintain said loops of a predetermined length during said stabilizing step.

11. A method according to claim 9 wherein tension is applied to the loops during said sewing step.

12. A method according to claim 11 wherein the same tension is maintained in each of said loops.

13. A method ofmanufacturing an endless mesh fabric comprising the steps of supporting a plurality of loops of rack filament in spaced relation upon a plurality of elongated support members mounted in fixed spaced relation to form a rack, moving said loops endlessly around a predetermined closed path defined by said members to move successive portions of said loops past first, second and third stations, at said first station depositing non-woven filler filaments on said loops of rack filament, at said second station sewing transversely of said loops of rack filament as successive portions thereof are moved past to sew said loops to said filler filaments to form an endless mesh fabric, and thereafter at said third station stabilizing successive portions of said fabric as they are moved past.

14. A method according to claim 13 wherein tension is applied to the loops to maintain said loops of predetermined length during said sewing and stabilizing steps.

15. A method according to claim 9 wherein said stabilizing step comprises gradually heating said fabric to a predetermined temperature as successive portions thereof are moved past to heat-shrink said fabric.

16. A method of manufacturing an endless mesh fabric comprising the steps of supporting a plurality of loops of rack filament in spaced relation upon a plurality of elongated support members mounted in fixed spaced relation to form a rack, moving said loops endlessly around a predetermined closed path defined by said members to move successive portions of said loops past a plurality of stations, sewing transversely of said loops of rack filament as successive portions thereof are moved past one of said stations to sew said loops together to form an endless mesh fabric, thereafter gradually heating successive portions of said fabric to a predetermined temperature as they are moved past another one of said stations to heatshrink said fabric, thereafter adding bonding agent to successive portions of said fabric as they are moved past one of said stations, and thereafter curing said bonding agent on successive portions of said fabric as they are moved past one of said stations.

17. A method according to claim wherein nonwoven filler filaments are deposited on said loops of rack filament prior to sewing, and wherein said sewing is effective to sew said loops to said filler filaments to form an endless mesh fabric.

18. A method according to claim 16 wherein said curing comprises heating successive portions thereof to a temperature no greater than said predetermined temperature as they are again moved past said station at which they were heat-shrunk.

19. A method of manufacturing an endless pre-shrunk mesh fabric comprising the steps of positioning a plurality of loops of rack filament in spaced relation upon a rack, applying tension to said loops of rack filament on said rack, moving said loops endlessly around a predetermined closed path defined by said rack, sewing transversely of said loops of rack filament to sew said loops together to form an endless mesh fabric while maintaining said loops in tension on said rack, and thereafter applying heat to said fabric to cause shrinkage thereof While maintaining said loops in tension on said rack to limit shrinkage in the direction of said loops.

20. An apparatus for the manufacture of endless mesh fabric comprising a rack including a plurality of elongated members mounted in fixed relationship to each other for receiving a plurality of loops of rack filament in spaced relation thereupon and supporting said loops for endless movement transversely of said members around a predetermined closed path, means for moving the loops about said path to move successive portions of said loops past first and second stations, sewing means at said first station for sewing transversely of said loops as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric, and means at said second station for stabilizing successive portions of said sewn fabric as they are moved past.

21. An apparatus according to claim 20 including tensioning means associated with one of said members for applying tension to the loops upon said rack to maintain said loops of a predetermined length.

22. An apparatus for the manufacture of continuous mesh fabric comprising a rack including a plurality of elongated members mounted in fixed relationship to each other to define a predetermined closed path of a predetermined length for receiving a plurality of loops of rack filament in spaced relation thereupon and supporting said loops for endless movement transversely of said members around said predetermined closed path, tensioning means associated with one of said members for applying tension to the loops upon said rack to maintain said loops of said predetermined length, means for moving the loops about said path to move successive portions of said loops past first and second stations, sewing means at said first station for sewing transversely of said loops as successive portions thereof are moved past to seW said loops together to form a continuous mesh fabric, and means at said second station for stabilizing said sewn fabric at said predetermined length by stabilizing successive portions thereof as they are moved past.

23. An apparatus for the manufacture of endless mesh fabric comprising a rack including a plurality of elon gated members mounted in fixed relationship to each other for receiving a plurality of loops of rack filament in spaced relation thereupon and supporting said loops for endless movement transversely of said members around a predetermined closed path, means for moving the loops about said path to move successive portions of said loops past a plurality of stations, sewing means at one of said stations for sewing tranversely of said loops as successive portions thereof are moved past to sew said loops together to form an endless mesh fabric, heating means at another of said stations for gradually heating said sewn fabric as successive portions thereof are mOVed past, and means at one of said stations for applying bonding agent to successive portions of said fabric as they are moved past.

24. An apparatus according to claim 23 including means at another of said stations for depositing non-woven filler filaments on said loops of rack filament, and wherein said sewing means is to sew said loops to said filler filaments to form said endless mesh fabric.

References Cited UNITED STATES PATENTS 3,025,622 3/1962 Hilton 1l22'62 X 3,042,568 7/1962 Ludowici et al 156-499 X 3,087,663 4/1963 Anderson 22644 3,160,124 12/1964 Cash l122 EARL M BERGERT, Primary Examiner I. C. GIL, Assistant Examiner US. Cl. X.R.

@3 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 9,612 Dated August 5, i969 Inventor) Charles A. Lee and Warren R. Furbeck It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 55, "it" should read "its" Column 7, line 5, after "filler" insert 99 line 25, "greater" should read "greatest" line 38, "roller" should be "rolled" Column 11, line 17, correct the spelling of "bottom" Column 13, line 8, correct the spelling of "encapsulate" line 65, after '"will" insert not SIGNED NN'D SEALED HAYS I970 (SEA!) Atteat:

hLFlctoh wmmnu E. w o R- mh. Commissioner of PM Attestmg Officer 

16. A METHOD OF MANUFACTURING AN ENDLESS MESH FABRIC COMPRISING THE STEPS OF SUPPORTING A PLURALITY OF LOOPS OF RACK FILAMENT IN SPACED RELATION UPON A PLURALITY OF ELONGATED SUPPORT MEMBERS MOUNTED IN FIXED SPACED RELATION TO FORM A RACK, MOVING SAID LOOPS ENDLESSLY AROUND A PREDETERMINED CLOSED PATH DEFINED BY SAID MEMBERS TO MOVE SUCCESSIVE PORTIONS OF SAID LOOPS PAST A PLURALITY OF STATIONS, SEWING TRANSVERSELY OF SAID LOOPS OF RACK FILAMENT AS SUCCESSIVE PORTIONS THEREOF ARE MOVED PAST ONE OF SAID STATIONS TO SEE SAID LOOPS TOGETHER TO FORM AN ENDLESS MESH FABRIC, THEREAFTER GRADUALLY HEATING SUCCESSIVE PORTIONS OF SAID FABRIC TO A PREDETERMINED TEMPERATURE AS THEY ARE MOVED PAST ANOTHER ONE OF SAID STATIONS TO HEATSHRINK SAID FABRIC, THEREAFTER ADDING BONDING AGENT TO SUCCESSIVE PORTIONS OF SAID FABRIC AS THEY ARE MOVED PAST ONE OF SAID STATIONS, AND THEREAFTER CURING SAID BONDING AGENT ON SUCCESSIVE PORTIONS OF SAID FABRIC AS THEY ARE MOVED PAST ONE OF SAID STATIONS. 